Different devices are used for repairing pipelines including those having a side wall consisting of two parts connected to each other and mounted around the pipeline defective area with a gap between the inner surface of the side wall and the outer surface of a pipe, which is filled with an uncured composite material (RU 113811 U1, Feb. 27, 2012, RU 129593 U1, Jun. 27, 2013, RU 2191317 C2, Oct. 20, 2002, RU 2378560 C1, Jan. 10, 2010, SK 1995 A3, Nov. 6, 1996, GB 2210134 A, Jun. 1, 1989). This method of repairing is referred to as “Composite sleeve technology”, CST for short.
CST has a variety of disadvantages, the main of which are:
1) a risk of non-uniform filling the space between a pipe and the side wall with the composite material, which does not provide guaranteed quality of repair, due to the air bubbles which can be formed during injection of a liquid composite material, particularly over the defect, which subsequently can cause pressing out metal into the cavity appeared and unsealing the pipeline;
2) the complexity of conducting arc welding of the outer metal side wall halves under the water, which constrains application of the given method for repairing underwater pipelines;
3) the necessity for providing active protection of the metal side wall against soil corrosion;
4) while having relatively low cost of materials and components of the repair structure, the high cost of organizational and technical measures for its installation, making repair in whole expansive.
A polymeric sleeve for repairing pipes with localized corrosion defects, lacking those disadvantages, consists of several layers of glass tape connected to each other by means of an adhesive layer and covers the pipeline circumferentially, wherein the sleeve is made of two separate preformed halves provided with hinged units engaged into each other at the ends and concatenated by means of the coupling shafts oriented in parallel in relation to the pipeline axis (RU 2219423 C2, Dec. 20, 2003). However, this repair structure has the other drastic disadvantages. Thus, due to the absence of the metal side wall this sleeve does not allow for bringing area being repaired to a defect free extent, since pretension, which is provided initially by heating the fiberglass sleeve and then by shrinkage thereof due to cooling down, is insufficient for fiberglass strength development to stop progression of the defect under the sleeve up to through hole. The reason for this is that the modulus of elasticity of fiberglass is at least seven times lower than the modulus of elasticity of steel. Furthermore, heating of a bulk fiberglass structure up to a temperature of about 160° C. is rather difficult in the field environment.
According to RU2224169 C2, Feb. 20, 2004, a sleeve for repairing a pipeline is known, wherein the sleeve comprises a tape, made of the preformed composite material in the form of two halfsleeves having a wavelike profile circumferentially, and an elastic pad facing the tape, and a smooth profile facing the pipeline.
The main disadvantage of such sleeve is utilising technical rubber having service life 200 000 hours, that is about 23 years, as elastic pad. Acting Russian norms and specifications for construction, exploitation and repair of main pipelines require that service life of materials used for these purposes is not less than 30 years. Therefore, the structure according to RU2224169 C2, Feb. 20, 2004, can not be considered as means for continuous repair of main pipelines.
According to US 2014048164 A1, Feb. 20, 2014, a method for repairing pipelines is provided, wherein one or more compression straps are installed around the outer circumferential surface of a pipe in the repair zone, corrosion-resistant coating is applied over the installed compression straps and the surface of the pipe in the repair zone, and a composite outer cover is wound around the corrosion-resistant (ground) coating applied in the repair zone.
This method for repairing does not provide a uniform pretension of the whole repair structure and tight squeezing of the pipeline defect area, therefore providing a uniform transfer of the radial load from the defect area to the outer sleeve cover can not be guaranteed, which is a drastic disadvantage of this repair structure.
The prototype for the provided invention is a sleeve (RU 148064 U1, Jul. 14, 2014), which comprises a sleeve mounted on a pipeline consisting of two halfsleeves, made of a cured composite material, and having a cylindrical inner surface corresponding to the pipeline diameter, and a conical outer surface, on the top of which a metallic side wall is mounted, the metallic side wall having a tapered shape, corresponding to the outer surface of the composite sleeve, and consisting of two halves preliminarily connected by means of arc welding. The composite sleeve resists compression and provides full load transfer from the defect area to the metallic side wall.
While the solution disclosed in the prototype for the provided invention lacks two of the most important CST disadvantages (1 and 4) described above, but it still has two disadvantages peculiar for CST, which are:
the complexity of conducting arc welding of the outer metal side wall halves under the water, which constrains application of the given method for repairing underwater pipelines;
the necessity for providing active protection of the metal side wall against soil corrosion.
The provided invention is intended to eliminate the disadvantages, described above.